Content for TS 26.131 Word version: 18.0.0

0… 5… 5.4… 5.4.3… 5.4.5… 5.4.7… 5.5… 5.8… 5.12… 6… 6.4… 6.4.3… 6.4.5… 6.4.7… 6.5… 6.8… 6.11… 6.12… 7… 7.4… 7.5… 7.8… 7.11… 7.12… 8… 8.4… 8.5… 8.8… 8.11… 8.12…

6.8 Distortion 6.8.1 Sending distortion (excluding electrical interface UE) 6.8.2 Receiving (excluding electrical interface UE) 6.8.3 Sending distortion (electrical interface UE) 6.8.4 Receiving distortion (electrical interface UE) 6.10 Sending performance in the presence of ambient noise
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6.8 Distortion p. 50

6.8.1 Sending distortion (excluding electrical interface UE) p. 50

The sending part shall meet the following distortion requirements:

Distortion shall be measured between the MRP and the SS audio output (output of the reference speech decoder of the SS). The ratio of signal-to-total distortion power measured with the proper noise weighting (see Table 4 of ITU-T Recommendation G.223) shall be above the limits given in Table 15.

Table 15: Limits for signal-to-total distortion ratio

Frequency (Hz)	Sending level (dBPa at the MRP)	Sending Ratio (dB)
315	-4,7	28
408	-4,7	32
510	-4,7	32
816	-4,7	32
1 020	5	30
	0	35
	-4.7	35
	-10	33
	-15	30
	-20	27

Limits for intermediate levels are found by drawing straight lines between the breaking points in Table 15 on a linear (dB signal level) - linear (dB ratio) scale.

Compliance of the sending distortion shall be checked by the test described in TS 26.132.

6.8.2 Receiving (excluding electrical interface UE) p. 50

The receiving part between the SS audio input (input of the reference speech encoder of the SS) and the applicable acoustic measurement point (DRP with diffuse-field correction for handset and headset modes; free field correction for hands-free modes) shall meet the requirements in this clause at the nominal setting of the volume control (except where another volume setting is specified):

The ratio of signal to total distortion power measured with the proper noise weighting (see Table 4 of ITU-T Recommendation G.223) shall be above the limits given in Table 16 when the sound pressure at the applicable acoustic measurement point is < 10 dBPa. For a sound pressure ≥ 10 dBPa at the applicable acoustic measurement point there is no distortion requirement.

Table 16: Limits for signal-to-total distortion ratio

Frequency (Hz)	Receiving level at the digital interface (dBm0)	Receiving ratio at nominal volume setting (dB)	Receiving ratio at maximum volume setting (dB)
315	-16	20
408	-16	28
510	-16	28
816	-16	28
1 020	0	25,5	tbd
	-3	31,5	tbd
	-10	33,5	tbd
	-16	33,5	tbd
	-20	33	tbd
	-30	30,5	tbd
	-40	22,5 (*)	tbd
	-45	17,5 (*)	tbd
NOTE: (*)For levels -40 and -45 dBm0 a lower signal-to-total distortion ratio may not be possible, and hence would not be regarded as a failing result. However, the obtained results would be reported.

Limits for intermediate levels are found by drawing straight lines between the breaking points in the Table on a linear (dB signal level) - linear (dB ratio) scale.

Compliance of the receiving distortion shall be checked by the appropriate method in TS 26.132.

6.8.3 Sending distortion (electrical interface UE) |R17| p. 51

The sending part shall meet the following distortion requirements:

Distortion shall be measured at the output of the electrical reference interface. The ratio of signal-to-total distortion power measured with the proper noise weighting (see Table 4 of ITU-T Recommendation G.223) shall be above the limits given in Table 16a1 for electrical interface UE with analogue connection and Table 16a2 for electrical interface UE with digital connection.

Table 16a1: Limits for signal-to-total distortion ratio for analogue connection

Frequency (Hz)	Sending level (dBV at at the output of the electrical reference interface)	Sending Ratio (dB)
315	-60	28
408	-60	32
510	-60	32
816	-60	32
1 020	-50	30
	-55	35
	-60	35
	-65	33
	-70	30
	-75	27

Table 16a2: Limits for signal-to-total distortion ratio for digital connection

Frequency (Hz)	Sending level (dBm0 at at the output of the electrical reference interface)	Sending Ratio (dB)
315	-16	28
408	-16	32
510	-16	32
816	-16	32
1 020	-6	30
	-11	35
	-16	35
	-21	33
	-26	30
	-31	27

Limits for intermediate levels are found by drawing straight lines between the breaking points in Table 16a1 and Table 16a2 on a linear (dB signal level) - linear (dB ratio) scale.

Compliance of the sending distortion shall be checked by the test described in TS 26.132.

6.8.4 Receiving distortion (electrical interface UE) |R17| p. 52

The receiving part between the SS audio input (input of the reference speech encoder of the SS) and applicable electric measurement point (input to the electrical reference interface) shall meet the requirements in this clause at the nominal setting of the volume control (except where another volume setting is specified):

The ratio of signal to total distortion power measured with the proper noise weighting (see Table 4 of ITU-T Recommendation G.223) shall be above the limits given in Table 16b.

Table 16b: Limits for signal-to-total distortion ratio

Frequency (Hz)	Receiving level at the digital interface (dBm0)	Receiving ratio at nominal volume setting (dB)	Receiving ratio at maximum volume setting (dB)
315	-16	20
408	-16	28
510	-16	28
816	-16	28
1 020	0	25,5	tbd
	-3	31,2	tbd
	-10	33,5	tbd
	-16	33,5	tbd
	-20	33	tbd
	-30	30,5	tbd
	-40	22,5 (*)	tbd
	-45	17,5 (*)	tbd
NOTE: (*)For levels -40 and -45 dBm0 a lower signal-to-total distortion ratio may not be possible, and hence would not be regarded as a failing result. However, the obtained results would be reported.

Limits for intermediate levels are found by drawing straight lines between the breaking points in Table 16b on a linear (dB signal level) - linear (dB ratio) scale.

Compliance of the receiving distortion shall be checked by the appropriate method in TS 26.132.

6.9 Void

6.10 Sending performance in the presence of ambient noise |R11| p. 53

6.10.1 General p. 53

For sending, in handset mode, the UE shall reduce the ambient noise picked up by the microphone(s) without significantly degrading the quality of the speech signal.

6.10.2 Connections with handset UE p. 53

The UE shall comply with the following requirements:

S-MOS-LQOw

The average of S-MOS-LQOw scores across all test conditions shall be ≥ 3.0
As a performance objective, the average of the S-MOS-LQOw scores across all test conditions should be ≥ 3.5

N-MOS-LQOw

The average of the N-MOS-LQOw scores across all test conditions shall be ≥ 2.3
As a performance objective, the average of N-MOS-LQOw scores across all test conditions should be ≥ 3.0

G-MOS-LQOw

No requirement.

Compliance shall be checked by the relevant tests described in TS 26.132.

6.10.3 Connections with Handheld hands-free UE |R13| p. 53

It is recommended that the UE meets the following performance objectives:

S-MOS-LQOw

The average of S-MOS-LQOw scores across all five test conditions should be ≥ 3.4

N-MOS-LQOw

The average of N-MOS-LQOw scores across all test conditions should be ≥ 2.3

G-MOS-LQOw

No performance objective.

Compliance shall be checked by the relevant tests described in TS 26.132.

6.10.4 Connections with electrical interface UE |R17| p. 53

The UE shall comply with the following requirements:

S-MOS-LQOn

The average of S-MOS-LQOn scores across all test conditions shall be ≥ 3.0
As a performance objective, the average of the S-MOS-LQOn scores across all test conditions should be ≥ 3.5

N-MOS-LQOn

The average of the N-MOS-LQOn scores across all test conditions shall be ≥ 2.3
As a performance objective, the average of N-MOS-LQOn scores across all test conditions should be ≥ 3.0

G-MOS-LQOn

No performance objective.

Compliance shall be checked by the relevant tests described in TS 26.132.